A semiconductor device such as a metal oxide semiconductor field effect transistor (MOSFET) may have a super junction structure to improve a breakdown voltage. A super junction structure can be formed by forming a plurality of openings in an n type semiconductor layer and then forming p type semiconductor layers in these openings. These p type semiconductor layers formed in the openings may include voids—that is, the openings may be incompletely filled with p type semiconductor materials. When the p type semiconductor layers formed in the openings have voids, the reliability of the semiconductor device is degraded and device manufacturing yield may be reduced.